2 Sam. v. 8. and 1 Chron. xi. 6.  The books of Moses, Joshua, and Judges, contain one continued history, down from the Creation to the death of Sampson.  Where the Pentateuch ends, the book of Joshua begins; and where the book of Joshua ends, the book of Judges begins.  Therefore all these books have been composed out of the writings of Moses, Joshua, and other records, by one and the same hand, after the beginning of the reign of Saul, and before the eighth year of David.  And Samuel was a sacred writer, 1 Sam. x. 25. acquainted with the history of Moses and the Judges, 1 Sam. xii. 8, 9, 10, 11, 12. and had leisure in the reign of Saul, and sufficient authority to compose these books.  He was a Prophet, and judged Israel all the days of his life, and was in the greatest esteem with the people; and the Law by which he was to judge the people was not to be published by less authority than his own, the Law-maker being not inferior to the judge.  And the book of Jasher, which is quoted in the book of Joshua, Josh. x. 13. was in being at the death of Saul, 2 Sam. i. 18.

At the dedication of the Temple of Solomon, when the Ark was brought into the most holy place, there was nothing in it but the two tables, 1 Kings viii. 9. and therefore when the Philistines took the Ark, they took out of it the book of the Law, and the golden pot of Manna, and Aaron’s Rod.  And this and other losses in the desolation of Israel, by the conquering Philistines, might give occasion to Samuel, after some respite from those enemies, to recollect the scattered writings of Moses and Joshua, and the records of the Patriarchs and Judges, and compose them in the form now extant.

The book of Ruth is a history of things done in the days of the Judges, and may be looked upon as an addition to the book of the Judges, written by the same author, and at the same time.  For it was written after the birth of David, Ruth iv. 17, 22. and not long after, because the history of Boaz and Ruth, the great grandfather and great grandmother of David, and that of their contemporaries, could not well be remembered above two or three generations.  And since this book derives the genealogy of David from Boaz and Ruth, and omits David’s elder brothers and his sons; it was written in honour of David, after he was anointed King by Samuel, and before he had children in Hebron, and by consequence in the reign of Saul.  It proceeds not to the history of David, and therefore seems to have been written presently after he was anointed.  They judge well therefore who ascribe to Samuel the books of Joshua, Judges, and Ruth.